A Relay Strategy Actuates Pre-Existing Trisubstituted Olefins in Monoterpenoids for Cross-Metathesis with Trisubstituted Alkenes

J Org Chem. 2020 Apr 3;85(7):4906-4917. doi: 10.1021/acs.joc.0c00067. Epub 2020 Mar 19.

Abstract

A retrosynthetic disconnection-reconnection analysis of epoxypolyenes-substrates that can undergo cyclization to podocarpane-type tricycles-reveals relay-actuated Δ6,7-functionalized monoterpenoid alcohols for ruthenium benzylidene catalyzed olefin cross-metathesis with homoprenyl benzenes. Successful implementation of this approach provided several epoxypolyenes as expected (E/Z, ca. 2-3:1). The method is further generalized for the cross-metathesis of pre-existing trisubstituted olefins in other relay-actuated Δ6,7-functionalized monoterpenoid alcohols with various other trisubstituted alkenes to form new trisubstituted olefins. Epoxypolyene cyclization of an enantiomerically pure, but geometrically impure, epoxypolyene substrate provides an enantiomerically pure, trans-fused, podocarpane-type tricycle (from the E-geometrical isomer).

Publication types

  • Research Support, Non-U.S. Gov't